There are a few cave paintings that kinda make you wonder. There's some ancient artwork, including temple engravings, that leave no doubt at all. But that's the closest we have for sure until there were written records. I figure that those old myths about deities turning into animals and impregnating women was from back in the days when we didn't understand exactly how reproduction works. Maybe they thought that a child could have multiple fathers, including spirits and animals. It's possible that bestiality was encouraged, for instance as a way for a baby to inherit a wolf's strength and speed. As for the wolves, maybe they started hanging around with human tribes for more than just table scraps!! That much is speculative, of course, but I don't think this goes too far out on a limb. From what I've heard, the ancient Egyptians enjoyed bestiality quite a bit, and sort of had an "anything goes" attitude about sex.